Toyota vitz 1.0 (2014) bad fuel economy

[pwuser148592960854]

I have vitz 2014 1.0 and its giving me a very bad fuel economy on highways. Yesterday i drove around 230km on motorway with Ac on at 120kmph and the mileage was slightly lower than 10km/ litre. Thats alarming i mean ideally i should be getting atleast around 15km/ litre on highways. Need some help.
One thing that i can point out is that i recently shifted from toyotal 20w50 engine oil (which they put in the engine without me knowing) to Total quartz 5w30 synthetic engine oil. Immediately after this, the fuel economy first improved to around 12-13km in the city and around 15 on long routes (both with AC). But now im facing the worst of all time.

[sfjsag]

If its 3 cylinder engine then dont be alarmed.
If its a 4 cylinder engine then there is a problem.

[Massive_One]

try driving it around 100 km/h or 90 ... then see how much economy you are getting.

I think for this 1 liter 3 cylinder engine at 120 km/h , expecting 15 km/l is a bit too much ..

[pwuser148592960854]

But isnt the 3 cylinder engine supposed to have a better fuel economy?

[pwuser148592960854]

But my concern is that i was getting 15km/l from the same car immediately after the oil change at same speed just a month ago. Then what could be causing the sudden decrease

[Massive_One]

ahan, if that's the case then most common culprit in these cars is the catalytic converter, when it gets choked, it affects the fuel economy a lot

[pwuser148592960854]

That might be the case. Thanks anyway

[azfarnb]

Broski, your engine i assume is cvt? CVTs inherently are the most efficient when driven at optimum speeds, say 80-90kmph and are the least efficient at the beginning and at the higher speeds. Their efficiency curve falls rapidly at 120. Familiarize yourself with the capacity of your engine by watching cvt engines explained by engineeringexplained on youtube. Use thin oils. Eg 5w30. 1KR engines tend to lose .5L per 1000k km or something of the sort so nothing to worry about. If your mileage is 100/150k plus then you may switch to 10w40. That works too

[Massive_One]

Broski, your engine i assume is cvt? CVTs inherently are the most efficient when driven at optimum speeds, say 80-90kmph and are the least efficient at the beginning and at the higher speeds. Their efficiency curve falls rapidly at 120.

but he said same engine was giving 15 km/l on long drives at same speeds before : /

[azfarnb]

It does not make any sense. The engineering behind the engine says otherwise maybe an anomaly, i dont know..

[pwuser148592960854]

I actually travelled the same distance a month ago at same speed and got 15km. I still dont get it myself

[mesumjanjua]

Get Catalytic Converter Cleaned.
Get Laser Iridium Plugs.
Get throttle Body cleaned aswell.
On next oil change get Engine flush before putting new Oil.
5W30 is best for your car. Make sure the oil you use is orignal. Get from authorized dealer.

[faizan7891]

A three cylinder vitz engine doen’t provide a good fuel efficiency anyway but again get the things listed above

[azfarnb]

Youre partially correct. A CVT would perform better if the cvt ratio is somewhere in the middle and not at extreme ends.

[anon35615524]

The problem isn't with the engine oil, but something else.

BTW, what's the current, genuine odo reading? Do get all the routine, regular maintenance done (if not done recently), and for more details, you can also check my thread. I own Vitz 2015 model, and I believe, many things are common in my car and your car.

[anon35615524]

Bro 1KR-FE is one of the fuel efficient engines in the world, and has also won awards Internationally many times, like engine of the year award.

Being 3 cylinder, it vibrates a lot, however, it isn't fragile, as is the general perception.